1. Field of the Invention
The present invention relates to a communication system, communication apparatus and method for setting communication parameters.
2. Description of the Related Art
To conduct communication via wireless LAN, it is necessary to set wireless LAN communication parameters (such as a network identifier called an SSID (Service Set ID), encryption key, authentication method and authentication key) among devices which conduct communications. Techniques have been proposed for simplifying the setting of communication parameters, which has been troublesome for users. For example, a method for setting communication parameters to be used between an access point and a station by transferring the parameters automatically from the access point to the station has been implemented into a product.
Also, Japanese Patent Laid-Open No. 2004-215232 (reference 1) describes a technique for setting communication parameters (encryption key) via wireless communication.
Also, Japanese Patent Laid-Open No. 2003-218875 (reference 2) describes a technique in which communication parameters are transmitted after being encrypted by an encryption method (WEP or common key, and devices which receive the communication parameters decrypt and set the parameters.
With the communication parameter setting methods described in references 1 and 2, when setting communication parameters for a device in operation (in communication), the operation must be stopped once before setting the communication parameters in order to specify the setting target device and to prevent leakage of the communication parameters.
In contrast, Japanese Patent Laid-Open No. 2003-338821 discloses a method for setting communication parameters without stopping the operation of a device in operation. This method uses default communication parameters to set operating communication parameters for a terminal which newly joins a network.
The conventional technique described above uses the default communication parameters for communication parameter transfer. Consequently, the transmitted communication parameters may be intercepted by malicious third parties (devices). Also, during communication parameter setting, operating communication parameters are switched to the default communication parameters, making it necessary for the communicating devices to perform the switching.